Printexc(3)							   OCaml library						       Printexc(3)

NAME

       Printexc - Facilities for printing exceptions.

Module
       Module	Printexc

Documentation
       Module Printexc
	: sig end

       Facilities for printing exceptions.

       val to_string : exn -> string

       Printexc.to_string e returns a string representation of the exception e .

       val print : ('a -> 'b) -> 'a -> 'b

       Printexc.print  fn  x applies fn to x and returns the result.  If the evaluation of fn x raises any exception, the name of the exception is
       printed on standard error output, and the exception is raised again.  The typical use is to catch and report exceptions that escape a func-
       tion application.

       val catch : ('a -> 'b) -> 'a -> 'b

       Printexc.catch  fn  x  is  similar to Printexc.print , but aborts the program with exit code 2 after printing the uncaught exception.  This
       function is deprecated: the runtime system is now able to print uncaught exceptions as precisely as Printexc.catch does.  Moreover, calling
       Printexc.catch  makes  it harder to track the location of the exception using the debugger or the stack backtrace facility.  So, do not use
       Printexc.catch in new code.

       val print_backtrace : Pervasives.out_channel -> unit

       Printexc.print_backtrace oc prints an exception backtrace on the output channel oc .  The backtrace lists the program locations	where  the
       most-recently raised exception was raised and where it was propagated through function calls.

       Since 3.11.0

       val get_backtrace : unit -> string

       Printexc.get_backtrace () returns a string containing the same exception backtrace that Printexc.print_backtrace would print.

       Since 3.11.0

       val record_backtrace : bool -> unit

       Printexc.record_backtrace  b  turns  recording of exception backtraces on (if b = true ) or off (if b = false ).  Initially, backtraces are
       not recorded, unless the b flag is given to the program through the OCAMLRUNPARAM variable.

       Since 3.11.0

       val backtrace_status : unit -> bool

       Printexc.backtrace_status() returns true if exception backtraces are currently recorded, false if not.

       Since 3.11.0

       val register_printer : (exn -> string option) -> unit

       Printexc.register_printer fn registers fn as an exception printer.  The printer should return None or raise an exception  if  it  does  not
       know  how to convert the passed exception, and Some s with s the resulting string if it can convert the passed exception. Exceptions raised
       by the printer are ignored.

       When converting an exception into a string, the printers will be invoked in the reverse order  of  their  registrations,  until	a  printer
       returns a Some s value (if no such printer exists, the runtime will use a generic printer).

       When using this mechanism, one should be aware that an exception backtrace is attached to the thread that saw it raised, rather than to the
       exception itself. Practically, it means that the code related to fn should not use the backtrace if  it	has  itself  raised  an  exception
       before.

       Since 3.11.2

OCamldoc							    2014-06-09							       Printexc(3)